The present invention relates generally to- electric switches and more particularly to rotary electric switches.
Electric switches are well known and widely used in the art.
Rotary electric switches, also commonly referred to simply as rotary switches in the art, are one well known type of electric switch. Rotary switches are primarily utilized in small appliances, such as electric fans, to regulate the application of power to the appliance through the rotation of an actuation shaft.
Rotary switches regulate the application of power to the appliance by selectively connecting various conductive leads for the appliance. Specifically, the motor of the appliance typically includes four output leads, or wires, which define the off, low, medium and high motor speeds. In addition, the power cord provides an input lead for the switch. Accordingly, the four output leads and the single input lead are electrically connected to the rotary switch. Manual rotation of the actuation shaft through a knob or other similar device selectively connects the input lead with each of the output leads so as to provide the appliance with its off, low, medium and high fan power settings.
In U.S. Pat. No. 5,072,078 to C.P. Rao et al., there is disclosed a rotary switch for small appliances, such as electric fans, comprising a base assembly and a cover assembly. The base assembly includes low, medium and high output terminals and a splice terminal in side-by-side relation along one edge thereof. The low, medium, high and splice terminals wedgingly receive the bared ends of a ribbon cable, or alternatively the bared ends of separate leads, with the input terminal and the opposite edge of the splice terminal being located at the opposite edge of the base. The cover assembly carries a rotor having contacts connected thereto whereby the rotor may be rotated so as to effect an electrical connection between either the low, medium or high output terminal and the input terminal.
The particular construction of the rotary switch disclosed in U.S. Pat. No. 5,072,078 to C.P. Rao et al. provides a number of important advantages over other types of rotary switches which are well known in the art.
As a first advantage, the rotary switch disclosed in U.S. Pat. No. 5,072,078 to C.P. Rao et al. is constructed to receive the bared ends of the four output leads in a closely spaced, side-by-side relationship along one side of the wall of the base of the rotary switch. As a consequence, the four output leads can be packaged together as a single ribbon cable. As can be appreciated, the packaging the four output leads into a single ribbon cable significantly simplifies the process for inserting the output leads into the rotary switch, thereby minimizing assembly time, which is highly desirable.
As a second advantage, the rotary switch disclosed in U.S. Pat. No. 5,072,078 to C.P. Rao et al. is constructed to wedgingly receive the bared ends of the various wires, this type of connection being commonly referred to as a xe2x80x9cpush-inxe2x80x9d connection in the art. Specifically, each of the output terminals comprise flat contact portions which are secured onto the bottom wall of the base assembly and upwardly-bent end portions which are disposed to enclose wire receiving apertures formed in the switch. Each of the output terminals is constructed of a resilient, electrically conductive material, such as beryllium copper, which enables the upstanding end portion of each terminal to flex inwardly when an electrical wire is pressed thereagainst. As a result of such inward flexion, each terminal is capable of wedgingly engaging an associated wire as the wire is inserted into the switch. It should be noted that the upstanding end portion of each terminal is often provided with a V-shaped groove which is shaped to receive a wire. Upon insertion of the wire into the switch, the V-shaped groove engages, or digs into, opposing sides of the wire. As can be appreciated, utilization of push-in connections of the type described above significantly simplifies the process for installing wires into the switch, which is highly desirable. Furthermore, the utilization of push-in connections of the type described above which include a V-shaped groove allow each terminal to engage an associated wire in two locations, thereby improving the quality of the contact between the terminal and the wire and significantly increasing the retentive force of the wire within the switch, which is highly desirable.
As a third advantage, the rotary switch disclosed in U.S. Pat. No. 5,072,078 to C.P. Rao et al. is constructed to include a plurality of partition walls on the inner surface of the cover plate. The plurality of partition walls are shaped to define relatively large, enclosed spaces which are adapted to receive the bared lead ends of the output wires. As can be appreciated, the partition walls serve to insure electrical isolation of the bared lead ends of the output wires, which is highly desirable.
Although well known and widely used in the art, the rotary switch disclosed in U.S. Pat. No. 5,072,078 to C.P. Rao et al. suffers from a notable drawback.
Specifically, it has been found that, during the assembly of the switch and the subsequent installation of the switch into an appliance, the switch is often subjected to a considerable amount of twisting and bending which, in turn, causes a considerable amount of twisting and bending of the wires inserted into the switch. The considerable amount of twisting and bending of the wires inserted into the switch creates a leverage action, or crowbar effect, which causes the wires to inwardly bend the end portions of the terminals. As a result, the inward bending of the end portions releases the locking forces of each terminal on its associated wire, thereby enabling the wires to be easily backed out and removed from the switch, which is highly undesirable.
It is an object of the present invention to provide a novel rotary switch.
It is another object of the present invention to provide a novel rotary switch which is adapted to receive a plurality of conductive leads.
It is yet another object of the present invention to provide a rotary switch as described above which is adapted to receive the plurality of leads in a closely disposed, side-by-side relationship.
It is still another object of the present invention to provide a rotary switch as described above which is adapted to electrically isolate the conductive leads therewithin.
It is yet still another object of the present invention to provide a rotary switch as described above which is adapted to securely retain each of the conductive leads therewithin.
It is another object of the present invention to provide a rotary switch as described above which is adapted to properly orientate the conductive leads as the conductive leads are guided therewithin.
It is yet another object of the present invention to provide a rotary switch as described above which is adapted to limit the movement of the conductive leads once inserted therewithin.
It is still another object of the present invention to provide a rotary switch as described above which is adapted to retain each of the conductive leads in proper electrical connection once inserted therewithin.
Accordingly, as one feature of the present invention, there is provided a rotary switch adapted to receive a plurality conductive wires, said rotary switch comprising a housing adapted to receive the plurality of conductive wires, said housing comprising a first inwardly tapered guide wall, the first inwardly tapered guide wall being shaped to define a slot into which a corresponding conductive wire can be disposed, a plurality of conductive terminals fixedly mounted onto said housing, each conductive terminal being adapted to electrically connect with an associated conductive wire, an actuation shaft rotatably mounted onto said housing, and a movable contact mounted onto said actuation shaft, wherein said movable contact selectively connects selected conductive terminals.
As another feature of the present invention, there is provided a housing for a rotary switch adapted to receive a plurality conductive wires, said housing comprising a base, and a cover mounted onto said base, said cover comprising a top surface, a bottom surface and at least one inwardly tapered guide wall formed on the bottom surface, the at least one inwardly tapered guide wall being shaped to define a slot into which a corresponding conductive wire can be disposed.
As another feature of the present invention, there is provided a cover for a rotary switch adapted to receive a plurality conductive wires, said cover comprising a top surface, a bottom surface, and at least one inwardly tapered guide wall formed on the bottom surface, the at least one inwardly tapered guide wall being shaped to define a slot into which a corresponding conductive wire can be disposed.
Additional objects, as well as features and advantages, of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. In the description, reference is made to the accompanying drawings which form a part thereof and in which is shown by way of illustration an embodiment for practicing the invention. The embodiment will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.